| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.75 | 0.99 | 0.64 |
| 2024 | 0.88 | 1.18 | 0.61 |
| 2023 | 0.7 | 0.9 | 0.48 |
| 2022 | 0.97 | 1.47 | 0.76 |
| 2021 | 0.74 | 1.27 | 0.47 |
| 2020 | 0.49 | 0.66 | 0.35 |
| 2019 | 0.45 | 0.56 | 0.37 |
| 2018 | 0.54 | 0.81 | 0.43 |
| 2017 | 0.83 | 1.11 | 0.6 |
| 2016 | 0.87 | 1.08 | 0.74 |
| 2015 | 0.94 | 1.43 | 0.71 |
| 2014 | 0.57 | 0.83 | 0.46 |
| 2013 | 0.72 | 0.95 | 0.55 |
| 2012 | 0.96 | 1.3 | 0.74 |
| 2011 | 1.42 | 1.82 | 0.98 |
| 2010 | 1.69 | 2.54 | 1.07 |
| 2009 | 2.09 | 3.31 | 0.89 |
| 2008 | 2.1 | 4.69 | 0.68 |
| 2007 | 4.49 | 6.16 | 2.1 |